1. Field of the Invention
The present invention relates to a composition in the form of an oil-in-water (O/W) emulsion comprising a high content of wax, and to its uses in cosmetics and dermatology, in particular for caring for, treating and/or making up the skin and/or mucous membranes, and more particularly for treating wrinkles and/or fine lines of the skin and/or for treating and/or protecting dry skin. The invention also relates to a process for preparing this composition, where at least one step of the process is carried out using a mixer-extruder.
2. Description of the Invention
It is well-known to use waxes in cosmetic creams in the form of emulsions intended for caring for human skin, in particular for the anti-wrinkle effects provided by these waxes. However, it is difficult to incorporate a high percentage of waxes into these compositions since waxes have a tendency to thicken the emulsions considerably. In addition, when a high percentage of waxes is incorporated into an emulsion, the emulsion is very difficult to apply to the skin since it does not slide. Moreover, a coarse effect appears on the skin. Such an emulsion is therefore unacceptable to users.
Furthermore, it is known to incorporate a high percentage of waxes into mascaras. However, compositions of this type cannot be used as care products on account of the drawbacks mentioned above.
Moreover, to prepare an emulsion containing waxes, it is necessary to melt the waxes in the fatty phase of the emulsion, in particular if it is desired, for example, to use waxes such as carnauba waxes which are particularly advantageous for their anti-wrinkle effect on the skin. It is thus necessary to heat the fatty phase up to 80-85.degree. C., which is particularly harmful when it is desired to introduce heat-sensitive compounds.
Therefore, a need exists for a composition containing a high percentage of waxes which is free of the drawbacks of the compositions described above.